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Zeiner, John (2009) THE EFFECTS OF INDUCED SLEEP FRAGMENTATION ON CARDIAC SYMPATHOVAGAL BALANCE. Master's Thesis, University of Pittsburgh. (Unpublished)

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Obstructive Sleep Apnea Hypopnea (OSAH) is a prevalent disorder that occurs in about 5% of the middle-aged adult population. Comprised of repetitive episodes of complete and/or partial upper airway obstruction during sleep, OSAH results in cyclic oxyhemoglobin desaturation-resaturation (e.g. intermittent hypoxia) and arousal from sleep (sleep fragmentation). Consequences of OSAH include increased risk of cardiovascular morbidity and mortality and elevated sympathetic activity (SA) during daytime wakefulness as well as sleep.This has potential clinical relevance because heightened SA is thought to be one mechanism explaining the association between OSAH and cardiovascular disease. Although OSAH is associated with increased sympathetic contribution to cardiac sympatho-vagal balance (SVB), the pathway mediating this effect (intermittent hypoxia, sleep fragmentation (SF) or both) is unclear. Because obstructive upper airway events in OSAH patients precipitate both physiologic phenomena in a generally concomitant manner, it has been difficult to sort the individual contributions of each in clinical populations.The aim of this study was to investigate the relationship between SVB and experimentally induced SF including examination of the possible interaction with being overweight in a healthy non-OSAH population. Twenty-nine subjects entered into a 4 night / 3 day sleep study to evaluate the effect of experimentally induced SF. Subjects provided a spectrum of body mass index (BMI) ranging from normal to overweight. Subjects experienced two nights of undisturbed sleep followed by two nights of fragmented sleep. Awake SVB reflected by heart rate variability was measured during wakefulness before and after a night of undisturbed sleep and a night of fragmented sleep. Sleep duration and architecture were assessed under both sleep conditions. SVB was decreased by transient changes from awake to sleep. SVB was affected by SF on an undisturbed night, but not a disturbed night. BMI had no effect. The public health significance of this study was that both OSAH and increased SVB have increased risk of cardiovascular disease; through improved understanding of the relationship between particular components of OSAH (SF or oxygenation-reoxygenation cycle) and increased SVB could lead to improved treatment of OSAH and the reduction of cardiovascular disease in the population.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Zeiner, John
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairArena, Vincentarena@pitt.eduARENA
Committee MemberYouk, Adaayouk@pitt.eduAYOUK
Committee MemberMarsh, Garygmarsh@pitt.eduGMARSH
Committee MemberSanders,
Date: 29 June 2009
Date Type: Completion
Defense Date: 16 April 2009
Approval Date: 29 June 2009
Submission Date: 31 July 2008
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Institution: University of Pittsburgh
Schools and Programs: School of Public Health > Biostatistics
Degree: MS - Master of Science
Thesis Type: Master's Thesis
Refereed: Yes
Uncontrolled Keywords: heart rate variability; HRV; obstructive sleep apnea; OSAH; sympathetic activity
Other ID:, etd-07312008-172728
Date Deposited: 10 Nov 2011 19:55
Last Modified: 15 Nov 2016 13:47


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